Community-acquired bacterial meningitis in older people

The Diagnostic Value of Cerebrospinal Fluid Lactate for Detection of Sepsis in Community-Acquired Bacterial Meningitis

Community-acquired bacterial meningitis conveys significant morbidity and mortality due to intracranial and systemic complications, and sepsis is a major contributor to the latter. While cerebrospinal fluid (CSF) analysis is essential in the diagnosis of bacterial meningitis, its predictive utility for detection of sepsis is unknown. We investigated the diagnostic performance of CSF parameters for sepsis defined by the Sepsis-3 criteria in a retrospective cohort of patients with community-acquired bacterial meningitis. Among 103 patients, 69.5% developed sepsis. CSF lactate was associated with sepsis with an odds ratio of 1.11 (p = 0.022), while CSF cell counts, glucose and protein levels were not (all p > 0.4). Employing the optimal cutoff of 8.2 mmol/L, elevated CSF lactate resulted in a sensitivity of 81.5% and specificity of 61.5% for sepsis. In exploratory analyses, CSF lactate was also associated with in-hospital mortality with an odds ratio of 1.21 (p = 0.011). Elevated CSF lactate might contribute to early diagnosis of sepsis as well as prognostication in patients with community-acquired bacterial meningitis.

[Diagnostic predictive factors in listeria meningitis]

PURPOSE

The purpose of this study was to elucidate the diagnostic predictive factors of listeria meningitis.

SUBJECTS AND METHOD

Twenty-eight patients with bacterial meningitis (age; 65.9 ± 14.8 years, 11 female) who were admitted to Chikamori Hospital from October 1, 2006 to December 31, 2021 were included. Bacterial meningitis was defined as cerebrospinal fluids (CSF) pleocytosis with evidence of bacterial infection in CSF or blood. The blood and CSF data were reviewed for analysis.

RESULTS

9 patients were diagnosed as listeria meningitis, 19 patients were in non-listeria meningitis. Multiple logistic regression analysis showed that higher CSF lymphocyte ratio was significantly associated with listeria meningitis (Odds ratio 1.123, 95% Confidence interval 1.006-1.2155, P = 0.039). CSF lymphocyte ratio of 30% or more was found to predict listeria meningitis with a sensitivity of 55.6% and a specificity of 100%.

CONCLUSION

CSF lymphocyte ratio may be useful for differentiating between listeria meningitis and non-listeria meningitis.

Clinical presentation, treatment, and outcome of 24 dogs with bacterial meningitis or meningoencephalitis without empyema (2010-2020)

BACKGROUND

Bacterial meningitis (BM) and meningoencephalitis (BMEM) are associated with high case fatality rates and neurologic sequelae in people, but limited data exists on outcome in dogs.

HYPOTHESIS/OBJECTIVES

To report the clinicopathologic features, treatment and outcome of BM/BMEM in dogs, with a focus on clinical presentation, relapse and long-term neurological deficits.

ANIMALS

Twenty-four client-owned dogs diagnosed with BM/BMEM without empyema.

METHODS

Retrospective case series of dogs diagnosed with BM/BMEM from 5 veterinary referral hospitals between January 2010 and August 2020.

RESULTS

Twenty-four dogs were included. Median duration of clinical signs was 2 days (range ≤24 hours to 30 days) and signs recorded included pyrexia (3) and cervical hyperesthesia (10). Neurological deficits were present in 18 dogs including altered mentation (12), ataxia (8), nonambulatory status (8), head tilt (8), and cranial nerve deficits (13). Intracellular bacteria were visualized on cerebrospinal fluid (CSF) analysis in 15/24 dogs, with positive CSF bacteriological culture in 8/21. Otitis media/interna (OMI) was diagnosed in 15/24 dogs, of which 6/15 dogs underwent total ear canal ablation and lateral bulla osteotomy. Twenty dogs survived to hospital discharge. Median duration of antibiotic administrations was 8 weeks (range, 2-16 weeks). Glucocorticoids were administered to 15 dogs. Median follow-up time was 92 days (range, 10-2233 days). Residual neurological deficits were reported in 9 dogs, with a single case of suspected relapse.

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinical signs were variable in dogs with BM/BMEM, the nidus of bacterial infection was often OMI and the majority of dogs made a full recovery with treatment.

Role of cerebrospinal fluid lactate in diagnosing meningitis in critically ill patients

BACKGROUND

Meningitis is a life-threatening clinical condition associated with high mortality and morbidity. Early diagnosis and specific treatment may improve outcomes. Lack of specific clinical signs or tests make the diagnosis challenging.

AIM

To assess the efficacy of cerebrospinal fluid (CSF) lactate in diagnosing meningitis in critically ill patients.

METHODS

A prospective, observational cohort study was carried out in a neuro-medical intensive care unit (ICU) over a 22 mo period. Adult patients, with suspected meningitis admitted in ICU, were serially recruited. Patients who refused consent, those with peripheral sensorineural deficit, or with any contraindication to lumber puncture were excluded. CSF cytology, bio-chemistry, lactates, culture and polymerase chain reaction based meningo-encephalitis panel were evaluated. Patients were divided in two groups based on clinical diagnosis of meningitis. The efficacy of CSF lactate in diagnosing meningitis was evaluated and compared with other tests.

RESULTS

Seventy-one patients were included and 23 were diagnosed with meningitis. The mean values of CSF total leucocyte count (TLC), proteins and lactates were significantly higher in meningitis group. There was a significant correlation of CSF lactate levels with CSF cultures and meningo-encephalitis panel. CSF lactate (> 2.72 mmol/L) showed good accuracy in diagnosing meningitis with an area under the curve of 0.81 (95% confidence interval: 0.69-0.93), sensitivity of 82.6%, and specificity 72.9%. These values were comparable to those of CSF TLC and protein. Twelve patients with bacterial meningitis had significantly higher CSF lactate (8.9 ± 4.7 mmol/L) than those with non-bacterial meningitis (4.2 ± 3.8 mmol/L), P = 0.006.

CONCLUSION

CSF lactate may be used to aid in our diagnosis of meningitis in ICU patients. CSF lactate (> 2.72 mmol/L) showed good accuracy, sensitivity, and specificity in diagnosing meningitis and may also help to differentiate between bacterial and non-bacterial meningitis.

A comparative study between children and adults with bacterial neuroinfections

Abstract.

Systemic Listeria monocytogenes infection in aged mice induces long-term neuroinflammation: the role of miR-155

BACKGROUND

Understanding mechanisms of pathologic neuroinflammation is essential for improving outcomes after central nervous system infections. Brain tissue-resident memory T cells (bT_RM) are recruited during central nervous system infection and promote pathogen control as well as noxious inflammation. Our prior studies in young mice showed optimal recruitment of CD8⁺ bT_RM during neuroinvasive Listeria monocytogenes (Lm) infection required miR-155, and was significantly inhibited by anti-miR-155 oligonucleotides. Since Lm is an important pathogen in the elderly, we hypothesized anti-miR-155 would also inhibit accumulation of CD8⁺ bT_RM in aged mice infected with Lm.

METHODS

Young (2 mo) and aged (> 18 mo) male C57BL/6 mice were infected intra-peritoneally with wild-type Lm, or avirulent Lm mutants lacking the genes required for intracellular motility (ΔactA) or phagosomal escape (Δhly), then were given antibiotics. Brain leukocytes and their intracellular cytokine production were quantified by flow cytometry >28d post-infection (p.i.). The role of miR-155 was tested by injecting mice with anti-miR-155 or control oligonucleotides along with antibiotics.

RESULTS

Aged mice had significantly more homeostatic CD8⁺ bT_RM than did young mice, which did not increase after infection with wild-type Lm despite 50% mortality, whereas young mice suffered no mortality after a larger inoculum. For direct comparison of post-infectious neuroinflammation after the same inoculum, young and aged mice were infected with 10⁷ CFU ΔactA Lm. This mutant caused no mortality and significantly increased CD8⁺ bT_RM 28d p.i. in both groups, whereas bone marrow-derived myeloid cells, particularly neutrophils, increased only in aged mice. Notably, anti-miR-155 reduced accumulation of brain myeloid cells in aged mice after infection, whereas CD8⁺ bT_RM were unaffected.

CONCLUSIONS

Systemic infection with Lm ΔactA is a novel model for studying infection-induced brain inflammation in aged mice without excessive mortality. CD8⁺ bT_RM increase in both young and aged mice after infection, whereas only in aged mice bone marrow-derived myeloid cells increase long-term. In aged mice, anti-miR-155 inhibits brain accumulation of myeloid cells, but not CD8⁺ bT_RM. These results suggest young and aged mice differ in manifestations and mechanisms of infection-induced neuroinflammation and give insight for developing therapies to ameliorate brain inflammation following severe infection in the elderly.

Community-acquired bacterial meningitis in patients of 80 years and older

Background

Advanced age is a risk factor for unfavorable outcome in community‐acquired bacterial meningitis, but clinical characteristics and outcome in meningitis patients of 80 years or older have not been defined.

Methods

We compared clinical characteristics and outcome of community‐acquired bacterial meningitis patients aged 80 years or older and adults under 80 years old within a prospective nationwide cohort study.

Results

Out of 2140 episodes identified between March 2006 and July 2018, 149 occurred in patients aged 80 years or older (7%). Common predisposing factors other than age were diabetes mellitus (25 of 148 [17%]), otitis or sinusitis (30 of 136 [22%]), and pneumonia (23 of 141 [16%]). The triad of fever, neck stiffness and altered consciousness was present in 60 of 139 (43%). The most common causative pathogen was Streptococcus pneumoniae (99 of 149 [66%]). Atypical causative pathogens, such as Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli, occurred more often compared to younger patients (49 of 149 [33%] vs 362 of 1991 [18%]; p < 0.001). Patients of 80 years and older had high case fatality rate (75 of 149 [50%]), but 45 of 149 (30%) had a favorable outcome. Characteristics associated with an unfavorable outcome were absence of otitis or sinusitis, presence of aphasia, mono‐ or hemiparesis, a lower score on the Glasgow Coma Scale, a higher heart rate, a higher blood C‐reactive protein concentration and CSF leukocytes <100 per mm³.

Conclusions

Bacterial meningitis in patients of 80 years of older is associated with high rates of unfavorable outcome and death. Atypical causative pathogens such as L. monocytogenes, S. aureus, and E. coli occur commonly and should be considered when starting empirical antimicrobial therapy in this age group.

CSF Neurofilament Light Chain Concentrations Predict Outcome in Bacterial Meningitis

Background and Objectives

Neurofilament light chain (NfL) is a biomarker for neuroaxonal damage and has been found to be elevated proportionally to the degree of neuronal damage in neurologic diseases. The objective of this study was to determine the prognostic accuracy of NfL concentrations on unfavorable outcome in adults with community-acquired bacterial meningitis.

Methods

We measured NfL concentration CSF samples from a prospective cohort study of adults with community-acquired bacterial meningitis in The Netherlands and determined associations between NfL CSF concentrations, clinical characteristics, and outcome in multivariate analyses. We identified independent predictors of an unfavorable outcome (Glasgow Outcome Scale scores 1–4) by logistic regression.

Results

CSF NfL concentrations were evaluated in 429 episodes of 425 patients with community-acquired bacterial meningitis. The median age of 429 episodes was 62 years (interquartile range, 50–69 years). Of note, 290 of 422 (68%) episodes presented with an altered mental status (Glasgow Coma Scale score < 14). Most common causative pathogens were Streptococcus pneumoniae (73%), Neisseria meningitidis (7%), and Listeria monocytogenes (5%). The overall case fatality rate was 62 of 429 (15%), and unfavorable outcome occurred in 57 (37%) of 429 episodes. In multivariate analysis, predictors of unfavorable outcome were older age (OR 1.03, 95% CI 1.01–1.05), cranial nerve palsy (OR 4, 95% CI 1.6–10.3), high serum C-reactive protein concentration (OR 1.3, 95% CI 1.01–1.05), and high CSF NfL concentration (OR 1.5, 95% CI 1.07–2.00). CSF NfL concentrations were higher in patients presenting with focal cerebral deficits (717 pg/mL [416–1,401] vs 412 pg/mL [278–731]; p < 0.001). The area under the curve (AUC) for predicting unfavorable outcome in bacterial meningitis of CSF NfL concentration was 0.69 (95% CI, 0.64–0.74).

Discussion

CSF NfL concentration is independently associated with unfavorable outcome in adults with community-acquired bacterial meningitis, suggesting that CSF NfL concentration may be a useful biomarker for prognostic assessment in bacterial meningitis.

Classification of Evidence

Can the level of NfL in CSF (the index test) predict unfavorable outcome in patients with bacterial meningitis, in a cohort of bacterial meningitis patients with a favorable and unfavorable outcome? This study provides Class II evidence that NfL level in CSF is a moderate predictor, with the AUC for predicting unfavorable outcome in bacterial meningitis being 0.69 (95% CI, 0.64–0.74).

Neuroinfectious Disease Emergencies

Neuroinfectious diseases can affect immunocompetent and immunosuppressed individuals and cause a variety of emergencies including meningitis, encephalitis, and abscess. Neurologic infections are frequently complicated by secondary injuries that also present emergently such as cerebrovascular disease, acute obstructive hydrocephalus, and seizure. In most cases, timely recognition and early treatment of infection can improve the morbidity and mortality of infectious neurologic emergencies.

Clinical utility of cerebrospinal fluid vitamin D-binding protein as a novel biomarker for the diagnosis of viral and bacterial CNS infections

Background

Rapid and accurate diagnosis of central nervous system (CNS) infections is important, and laboratory tests help diagnose CNS infections. Even when the patient has symptoms, laboratory tests often do not reveal any specific findings. The potential of vitamin D-binding protein (VDBP) to be used as a biomarker for viral and bacterial CNS infections was studied.

Methods

A total of 302 subjects with suspected CNS infection who underwent lumbar puncture were included. Clinical and laboratory data were collected retrospectively. VDBP levels were measured in the cerebrospinal fluid (CSF) samples. Genotyping for the GC gene encoding VDBP was also performed. VDBP levels were analyzed and compared by CNS infection, pathogen, CSF opening pressure, and GC genotype.

Results

A CNS infection group (n = 90) and a non-CNS infection group (n = 212) were studied. In terms of its receiver operating characteristic, CSF VDBP showed an area under the curve of 0.726 for the diagnosis of CNS infection. CSF VDBP levels were significantly different between the CNS infection and non-infection groups. The CNS infection group with enterovirus showed a statistically lower distribution of CSF VDBP levels than the other virus groups. The group with CSF opening pressure > 25 cmH₂O showed higher CSF VDBP levels than the other groups. There was no significant difference in GC gene allele distribution between the CNS infection and non-infection groups.

Conclusions

CSF VDBP levels were increased in patients with CNS infection. The CSF VDBP showed potential as a new biomarker for viral and bacterial CNS infections.

Neurologic Emergencies at the Extremes of Age

The diagnosis and management of neurologic conditions are more complex at the extremes of age than in the average adult. In the pediatric population, neurologic emergencies are somewhat rare and some may require emergent consultation. In older adults, geriatric physiologic changes with increased comorbidities leads to atypical presentations and worsened outcomes. The unique considerations regarding emergency department presentation and management of stroke and altered mental status in both age groups is discussed, in addition to seizures and intracranial hemorrhage in pediatrics, and Parkinson's disease and meningitis in the geriatric population.

Unusual presentation of meningococcal meningitis in the elderly and utility of CSF PCR testing

We present an unusual case of a previously healthy 74-year-old man who presented with diffuse weakness, severe myalgias, petechial palmar rash and hypotension, but without fever, altered mental status, nuchal rigidity or headache, who was ultimately found through PCR testing to have meningococcal meningitis.

Readmissions after hospital care for meningitis in the United States

BACKGROUND

Our objectives were to (1) characterize patient and clinical characteristics of adults hospitalized with meningitis; (2) describe meningitis hospitalization outcomes, including 30- and 90-day readmissions; and (3) determine whether clinical, patient, or index hospitalization characteristics are associated with readmission and readmission outcomes.

METHODS

This retrospective study of the 2014 National Readmissions Database extracted data on hospitalized adults with a principal diagnosis of meningitis and examined hospitalization outcomes using descriptive statistics. Logistic regression models were built to determine whether characteristics were associated with 30- or 90-day readmissions.

RESULTS

For the 30-day readmission analyses, 18,883 adults qualified. Meningitis hospitalizations commonly involved adults 25 to 54 years of age who were insured by private carriers. The readmission rates were 7.0% at 30 days and 11.4% at 90 days. Readmission was associated with greater comorbidity burden (2 conditions: adjusted odds ratio [AOR] = 1.60, range 1.24-2.08; 3 conditions: AOR = 1.92, range 1.43-2.58; 4+ conditions: AOR = 2.68, range 2.04-3.51 vs 0 or 1 condition), public insurance (Medicare: AOR = 1.85, range 1.30-2.62; Medicaid: AOR = 1.48, range 1.16-1.90 vs private insurance), and medical error (AOR = 1.43, range 1.07-1.91). Readmissions were most often for meningitis, septicemia, or medical complications.

CONCLUSIONS

Readmission after hospitalization for meningitis is associated with both fixed and modifiable factors. More research is needed to determine which post-meningitis readmissions are preventable.

The cause of death in bacterial meningitis

Background

Death from bacterial meningitis is rarely attributed to the actual event causing death.

The present study therefore categorized and characterized the cause and time of death due to bacterial meningitis.

Methods

In a cohort of patients > 15 years of age with community acquired bacterial meningitis the medical records were reviewed, and a clinical cause of death categorized into six main categories: 1) CNS complications, 2) Systemic complications, 3) Combination of systemic and CNS complications, 4) Sudden death, 5) Withdrawal of care, or 6) Unknown.

Results

We identified 358 patients of which 84 (23%) died in-hospital. Causes of death were ascribed to CNS complications in 43%, Systemic complications in 39%, Combined CNS and systemic complications in 4%, Sudden death in 7% and withdrawal of care in 5%. Brain herniation, circulatory failure, intractable seizures and other brain injury were the most common specific causes of death within 14 days from admission (55%).

Conclusion

Fatal complications due to the primary infection – meningitis - is most common within 14 days of admission. The diversity of complications causing death in meningitis suggest that determining the clinical cause of death is essential to the evaluation of novel treatment strategies.

Community-acquired pneumonia in patients with bacterial meningitis: a prospective nationwide cohort study

OBJECTIVE

Pneumonia is considered a focus of infection in patients presenting with community-acquired bacterial meningitis but the impact on disease course is unclear. The aim was to study presenting characteristics, clinical course and outcome of meningitis patients with co-existing pneumonia on admission.

METHODS

We evaluated adult patients with community-acquired bacterial meningitis with pneumonia on admission in a nationwide, prospective cohort performed from March 2006 to June 2017. We performed logistic regression analysis to identify clinical characteristics predictive of pneumonia on admission, and to quantify the effect of pneumonia on outcome.

RESULTS

Pneumonia was diagnosed on admission in 315 of 1852 (17%) bacterial meningitis episodes and confirmed by chest X-ray in 256 of 308 (83%) episodes. Streptococcus pneumoniae was the causative organism in 256 of 315 episodes (81%). Pneumonia on admission was associated with advanced age (OR 1.03 per year increase, 95% CI 1.02-1.04, p < 0.001), alcoholism (OR 1.96, 95% CI 1.23-3.14, p 0.004), cancer (OR 1.54, 95% CI 1.12-2.13, p 0.008), absence of otitis or sinusitis (OR 0.44, 95% CI 0.32-0.59, p < 0.001) and S. pneumoniae (OR 2.14, 95% CI 1.55-2.95, p < 0.001) in the multivariate analysis. An unfavourable outcome defined as a score of 1-4 on the Glasgow Outcome Scale was observed in 172 (55%) episodes and 87 patients (28%) died. Pneumonia on admission was independently associated with unfavourable outcome and mortality in the multivariate analysis (OR 1.48, 95% CI 1.12-1.96; p 0.005).

CONCLUSION

Pneumonia on admission in bacterial meningitis is a frequent coexisting infection and is independently associated with unfavourable outcome and mortality.

Risk factors and prognosis of seizures in adults with community-acquired bacterial meningitis in Denmark: observational cohort studies

OBJECTIVE

To examine predefined risk factors and outcome of seizures in community-acquired bacterial meningitis (CABM).

DESIGN

Observational cohort studies SETTING: Denmark PARTICIPANTS: In the derivation cohort, we retrospectively included all adults (>15 years of age) with CABM in North Denmark Region from 1998 to 2014 and at Hvidovre and Hillerød hospitals from 2003 to 2014. In the validation cohort, we prospectively included all adults (>18 years of age) with CABM treated at all departments of infectious diseases in Denmark from 2015 to 2017.

PRIMARY AND SECONDARY OUTCOME MEASURES

In the derivation cohort, we used modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals for predefined risk factors for seizures during CABM as well as for risks of death and unfavourable outcome assessed by the Glasgow Outcome Scale score (1-4). Next, results were validated in the validation cohort.

RESULTS

In the derivation cohort (n=358), risk factors for seizures at any time were pneumococcal aetiology (RR 1.69, 1.01-2.83) and abnormal cranial imaging (RR 2.27, 1.46-3.53), while the impact of age >65 years and immunocompromise was more uncertain. Examining seizures occurring after admission, risk factors were abnormal cranial imaging (RR 2.23, 1.40-3.54) and immunocompromise (RR 1.59, 1.01-2.50). Seizures at any time were associated with increased risks of in-hospital mortality (RR 1.45, 1.01-2.09) and unfavourable outcome at discharge (RR 1.27, 1.02-1.60). In the validation cohort (n=379), pneumococcal aetiology (RR 1.69, 1.10-2.59) and abnormal cranial imaging (RR 1.68, 1.09-2.59) were confirmed as risk factors for seizures at any time. For seizures occurring after admission, only pneumococcal meningitis (RR 1.92, 1.12-3.29) remained significant. Seizures at any time were also associated with in-hospital mortality (RR 3.26, 1.83-5.80) and unfavourable outcome (RR 1.23, 1.00-1.52) in this cohort.

CONCLUSIONS

Pneumococcal aetiology, immunocompromise and abnormal cranial imaging were risk factors for seizures in CABM. Seizures were strongly associated with mortality and unfavourable outcome.

Cerebrospinal fluid vitamin D-binding protein as a new biomarker for the diagnosis of meningitis

BACKGROUND

Meningitis is an inflammatory process involving meninges. It is difficult to diagnose because of the absence of a diagnostic biomarker. We first report here the possibility of cerebrospinal fluid (CSF) vitamin D-binding protein (VDBP) as a new biomarker for the diagnosis of meningitis.

METHODS

This prospective study enrolled a total of 102 subjects (58 patients with non-neurologic disease, 17 patients with meningitis, and 27 patients with other neurologic diseases) from 2017 to 2018. CSF and blood samples were collected in pairs. Total 25(OH)D in CSF and serum and VDBP levels in serum were measured. GC genotyping was also performed to determine polymorphisms of rs4588 and rs7041. CSF total 25(OH)D and VDBP levels were compared with serum total 25(OH)D and VDBP levels according to disease (meningitis vs. non-meningitis). Receiver operating characteristic (ROC) analysis for the diagnosis of meningitis using CSF VDBP level was performed.

RESULTS

Mean CSF VDBP and serum VDBP levels of all patients were 1.48 ± 1.32 and 181.28 ± 56.90 μg/mL, respectively. CSF VDBP level in the meningitis disease group (3.20 ± 1.49 μg/mL) was significantly (P < 0.001) higher than that in other disease groups. According to ROC curve analysis, the appropriate cut-off value for CSF VDBP was 1.96 μg/mL, showing sensitivity of 82.4% and specificity of 85.9%. AUC of CSF VDBP was 0.879 (95% CI: 0.789-0.962).

CONCLUSIONS

CSF VDBP level showed very good diagnostic performance. It could be used as a potential biomarker for the diagnosis of meningitis.

Age does not influence the disease course in a mouse model of Streptococcus pneumoniae serotype 3 meningitis

In order to elucidate the causes for the increased mortality of aged patients with bacterial central nervous system (CNS) infections, we compared the course of Streptococcus pneumoniae (S. pneumoniae) meningitis in aged and young mice. Aged (21.2 ± 3.1 months, n = 40) and young (3.2 ± 0.9 months, n = 42) C57BL/6N and B6/SJL mice were infected by intracerebral injection of 50–70 CFU S. pneumoniae serotype 3 and monitored for 15 days. Aged and young mice did not differ concerning mortality (35% versus 38%), weight loss, development of clinical symptoms, bacterial concentrations in cerebellum and spleen as well as the number of leukocytes infiltrating the CNS. In contrast to results from our geriatric mouse model of Escherichia coli (E. coli) meningitis, where aged mice showed a higher mortality and an impaired elimination of bacteria, we did not find any differences between aged and young mice after intracerebral infection with S. pneumoniae serotype 3. This indicates that the increased susceptibility of aged mice to bacterial CNS infections is pathogen-specific: It appears less prominent in infections caused by hardly phagocytable pathogens with thick capsules like S. pneumoniae serotype 3, where the age-related decline of the phagocytic capacity of microglia and macrophages has a minor influence on the disease course.

Prophylactic Palmitoylethanolamide Prolongs Survival and Decreases Detrimental Inflammation in Aged Mice With Bacterial Meningitis

Easy-to-achieve interventions to promote healthy longevity are desired to diminish the incidence and severity of infections, as well as associated disability upon recovery. The dietary supplement palmitoylethanolamide (PEA) exerts anti-inflammatory and neuroprotective properties. Here, we investigated the effect of prophylactic PEA on the early immune response, clinical course, and survival of old mice after intracerebral E. coli K1 infection. Nineteen-month-old wild type mice were treated intraperitoneally with two doses of either 0.1 mg PEA/kg in 250 μl vehicle solution (n = 19) or with 250 μl vehicle solution only as controls (n = 19), 12 h and 30 min prior to intracerebral E. coli K1 infection. The intraperitoneal route was chosen to reduce distress in mice and to ensure exact dosing. Survival time, bacterial loads in cerebellum, blood, spleen, liver, and microglia counts and activation scores in the brain were evaluated. We measured the levels of IL-1β, IL-6, MIP-1α, and CXCL1 in cerebellum and spleen, as well as of bioactive lipids in serum in PEA- and vehicle-treated animals 24 h after infection. In the absence of antibiotic therapy, the median survival time of PEA-pre-treated infected mice was prolonged by 18 h compared to mice of the vehicle-pre-treated infected group (P = 0.031). PEA prophylaxis delayed the onset of clinical symptoms (P = 0.037). This protective effect was associated with lower bacterial loads in the spleen, liver, and blood compared to those of vehicle-injected animals (P ≤ 0.037). PEA-pre-treated animals showed diminished levels of pro-inflammatory cytokines and chemokines in spleen 24 h after infection, as well as reduced serum concentrations of arachidonic acid and of one of its metabolites, 20-hydroxyeicosatetraenoic acid. In the brain, prophylactic PEA tended to reduce bacterial titers and attenuated microglial activation in aged infected animals (P = 0.042). Our findings suggest that prophylactic PEA can counteract infection associated detrimental responses in old animals. Accordingly, PEA treatment slowed the onset of infection symptoms and prolonged the survival of old infected mice. In a clinical setting, prophylactic administration of PEA might extend the potential therapeutic window where antibiotic therapy can be initiated to rescue elderly patients.

Healthcare-Associated Meningitis or Ventriculitis in Older Adults

BACKGROUND/OBJECTIVES

Healthcare-associated meningitis or ventriculitis (HCAMV) is a serious and life-threatening complication of invasive neurosurgical procedures or penetrating head trauma. Older adults are at higher risk of adverse outcomes in community-acquired meningitis but studies of HCAMV are lacking. Therefore, we perform the study to define the differences in clinical outcomes between older and younger adults with HCAMV.

DESIGN

Retrospective study.

SETTING

A large tertiary care hospital in Houston, Texas, from July 2003 to November 2014.

PARTICIPANTS

Adults with a diagnosis of HCAMV (N = 160) aged ≥65 (n = 35), aged 18-64 (n = 125).

MEASUREMENTS

Demographic characteristics, clinical presentation, laboratory results, treatments, and outcomes (Glasgow Outcome Scale).

RESULTS

Older adults had more comorbidities and CSF abnormalities [pleocytosis, high cerebrospinal fluid (CSF) protein, low CSF glucose) and were more likely to have altered mental status than younger adults (P < .05). An adverse clinical outcome was seen in 142 participants (89%) (death (n = 18, 11%), persistent vegetative state (n = 26, 16%), severe disability (n = 68, 43%), moderate disability (n = 30, 19%). There was no difference in adverse outcomes between older (97%) and younger (86%) adults (P = .13). On logistic regression analysis, abnormal neurological examination (adjusted odds ratio (aOR) = 7.13, 95% confidence interval (CI) = 2.15-23.63, P = .001) and mechanical ventilation (aOR = 11.03, 95% CI = 1.35-90.51, P = .02) were associated with adverse clinical outcomes.

CONCLUSION

Older adults with HCAMV have more comorbidities and CSF abnormalities and are more likely to have altered mental status than younger adults but have similar high rates of adverse clinical outcomes.

Neurologic Emergencies in the Elderly

Neurologic diseases are a major cause of death and disability in elderly patients. Due to the physiologic changes and increased comorbidities that occur as people age, neurologic diseases are more common in geriatric patients and a major cause of death and disability in this population. This article discusses the elderly patient presenting to the emergency department with acute ischemic stroke, transient ischemic attack, intracerebral hemorrhage, subarachnoid hemorrhage, chronic subdural hematoma, traumatic brain injury, seizures, and central nervous system infections. This article reviews the subtle presentations, difficult workups, and complicated treatment decisions as they pertain to our older patients."

Sepsis and Other Infectious Disease Emergencies in the Elderly

Waning immunity and declining anatomic and physiologic defenses render the elder vulnerable to a wide range of infectious diseases. Clinical presentations are often atypical and muted, favoring global changes in mental status and function over febrile responses or localizing symptoms. This review encompasses early recognition, evaluation, and appropriate management of these common infections specifically in the context of elders presenting to the emergency department. With enhanced understanding and appreciation of the unique aspects of infections in the elderly, emergency physicians can play an integral part in reducing the morbidity and mortality associated with these often debilitating and life-threatening diseases.

The Optimal Management of Acute Febrile Encephalopathy in the Aged Patient: A Systematic Review

The elderly comprise less than 13 percent of world population. Nonetheless, they represent nearly half of all hospitalized adults. Acute change in mental status from baseline is commonly seen among the elderly even when the main process does not involve the central nervous system. The term "geriatric syndrome" is used to capture those clinical conditions in older people that do not fit into discrete disease categories, including delirium, falls, frailty, dizziness, syncope, and urinary incontinence. Despite the growing number of elderly population, especially those who require hospitalization and the high burden of common infections accompanied by encephalopathy among them, there are several unresolved questions regarding the optimal management they deserve. The questions posed in this systematic review concern the need to rule out CNS infection in all elderly patients presented with fever and altered mental status in the routine management of febrile encephalopathy. In doing so, we sought to identify all potentially relevant articles using searches of web-based databases with no language restriction. Finally, we reviewed 93 research articles that were relevant to each part of our study. No prospective study was found to address how should AFE in the aged be optimally managed.

Higher mortality and impaired elimination of bacteria in aged mice after intracerebral infection with E. coli are associated with an age-related decline of microglia and macrophage functions

Incidence and mortality of bacterial meningitis are strongly increased in aged compared to younger adults demanding new strategies to improve prevention and therapy of bacterial central nervous system (CNS) infections the elderly.

Here, we established a geriatric mouse model for an intracerebral E. coli infection which reflects the clinical situation in aged patients: After intracerebral challenge with E. coli K1, aged mice showed a higher mortality, a faster development of clinical symptoms, and a more pronounced weight loss. Elimination of bacteria and systemic inflammatory response were impaired in aged mice, however, the number of infiltrating leukocytes and microglial cells in the CNS of aged and young mice did not differ substantially.

In vitro, primary microglial cells and peritoneal macrophages from aged mice phagocytosed less E. coli and released less NO and cyto-/chemokines compared to cells from young mice both without activation and after stimulation by agonists of TLR 2, 4, and 9.

Our results suggest that the age-related decline of microglia and macrophage functions plays an essential role for the higher susceptibility of aged mice to intracerebral infections. Strategies to improve the phagocytic potential of aged microglial cells and macrophages appear promising for prevention and treatment of CNS infections in elderly patients.

Bacterial meningitis: insights into pathogenesis and evaluation of new treatment options: a perspective from experimental studies

Bacterial meningitis is associated with high mortality and morbidity rates. Bacterial components induce an overshooting inflammatory reaction, eventually leading to brain damage. Pathological correlates of neurofunctional deficits include cortical necrosis, damage of the inner ear and hippocampal apoptosis. The hippocampal dentate gyrus is important for memory acquisition and harbors a neuronal stem cell niche, thus being potentially well equipped for regeneration. Adjuvant therapies aimed at decreasing the inflammatory reaction, for example, dexamethasone, and those protecting the brain from injury have been evaluated in animal models of the disease. They include nonbacteriolytic antibiotics (e.g., daptomycin), metalloproteinase inhibitors and modulators of the immunological response, for example, granulocyte colony-stimulating factor. Increasing research interest has recently been focused on interventions aimed at supporting regenerative processes.

Adult bacterial meningitis: earlier treatment and improved outcome following guideline revision promoting prompt lumbar puncture

BACKGROUND

In suspected acute bacterial meningitis (ABM), cerebral computerized tomography (CT) is recommended before lumbar puncture (LP) if mental impairment. Despite guideline emphasis on early treatment, performing CT prior to LP implies a risk of delayed treatment and unfavorable outcome. Therefore, Swedish guidelines were revised in 2009, deleting impaired mental status as a contraindication for LP without prior CT scan. The aim of the present study was to evaluate the guideline revision.

METHODS

The Swedish quality registry for community-acquired ABM was analyzed retrospectively. Door-to-antibiotic time and outcome were compared among patients treated 2005-2009 (n=394) and 2010-2012 (n=318). The effect of different LP-CT sequences was analyzed during 2008-2012.

RESULTS

Adequate treatment was started 1.2 hours earlier, and significantly more patients were treated <2 hours from admission 2010-2012 than 2005-2009. Compared with CT before LP, immediate LP resulted in 1.6 hours earlier treatment, significant increase in door-to-antibiotic times of <1 and <2 hours, and a favorable outcome. In 2010-2012, mortality was lower (6.9% vs 11.7%) and the risk of sequelae at follow-up decreased (38% vs 49%) in comparison with 2005-2009. Treatment delay resulted in a significantly increased risk for fatal outcome, with a relative increase in mortality of 12.6% per hour of delay.

CONCLUSIONS

The deletion of impaired mental status as contraindication for prompt LP and LP without prior CT scan are associated with significantly earlier treatment and a favorable outcome. A revision of current international guidelines should be considered.

Neuro-intensive treatment targeting intracranial hypertension improves outcome in severe bacterial meningitis: an intervention-control study

OBJECTIVE

To evaluate the efficacy of early intracranial pressure (ICP)-targeted treatment, compared to standard intensive care, in adults with community acquired acute bacterial meningitis (ABM) and severely impaired consciousness.

DESIGN

A prospectively designed intervention-control comparison study of adult cases from September 2004 to January 2012.

PATIENTS

Included patients were confirmed ABM-cases, aged 16-75 years, with severely impaired mental status on admission. Fifty-two patients, given ICP-targeted treatment at the neuro-intensive care unit, and 53 control cases, treated with conventional intensive care, were included. All the patients received intensive care with mechanical ventilation, sedation, antibiotics and corticosteroids according to current guidelines. Additional ICP-treatment in the intervention group included cerebrospinal fluid drainage using external ventricular catheters (n = 48), osmotherapy (n = 21), hyperventilation (n = 13), external cooling (n = 9), gram-doses of methylprednisolone (n = 3) and deep barbiturate sedation (n = 2) aiming at ICP <20 mmHg and a cerebral perfusion pressure of >50 mmHg.

MEASUREMENTS

The primary endpoint was mortality at two months and secondary endpoint was Glasgow outcome score and hearing ability at follow-up at 2-6 months.

OUTCOMES

The mortality was significantly lower in the intervention group compared to controls, 5/52 (10%) versus 16/53 (30%; relative risk reduction 68%; p<0.05). Furthermore, only 17 patients (32%) in the control group fully recovered compared to 28 (54%) in the intervention group (relative risk reduction 40%; p<0.05).

CONCLUSIONS

Early neuro-intensive care using ICP-targeted therapy, mainly cerebrospinal fluid drainage, reduces mortality and improves the overall outcome in adult patients with ABM and severely impaired mental status on admission.

Bacterial meningitis

Bacterial meningitis is a neurologic emergency. Vaccination against common pathogens has decreased the burden of disease. Early diagnosis and rapid initiation of empiric antimicrobial and adjunctive therapy are vital. Therapy should be initiated as soon as blood cultures have been obtained, preceding any imaging studies. Clinical signs suggestive of bacterial meningitis include fever, headache, meningismus, and an altered level of consciousness but signs may be scarce in children, in the elderly, and in meningococcal disease. Host genetic factors are major determinants of susceptibility to meningococcal and pneumococcal disease. Dexamethasone therapy has been implemented as adjunctive treatment of adults with pneumococcal meningitis. Adequate and prompt treatment of bacterial meningitis is critical to outcome. In this chapter we review the epidemiology, pathophysiology, and management of bacterial meningitis.

Listeriosis at a tertiary care hospital in beijing, china: high prevalence of nonclustered healthcare-associated cases among adult patients

Thirty-eight cases of listeriosis over a 12-year period from inpatients at a tertiary care hospital in China were reviewed. We found a high prevalence of healthcare-associated cases that did not cluster in time and space.

Background. Listeriosis is an emerging infectious disease associated with high mortality. There are few published reports from East Asia and developing countries. Our goal was to describe the clinical characteristics and outcomes of patients diagnosed with Listeria monocytogenes at a tertiary care hospital in Beijing, China.

Methods. Peking Union Medical College Hospital (PUMCH), an 1800-bed hospital, consists of 2 campuses that house different medical departments. We retrospectively reviewed all culture-proven cases of listeriosis occurring at PUMCH between 1999 and 2011. Point estimates and 95% confidence intervals are presented.

Results. There were 38 patients with listeriosis: 5 neonatal, 8 maternal, and 25 nonmaternal. The median age of the adult nonmaternal patients was 47 (range, 18–79) years with a female predominance (72%). Forty percent (n = 10) had an underlying rheumatic disease. Forty-four percent of cases (n = 11) were healthcare-associated infections occurring a median of 20 (range, 3–44) days after hospital admission. Only 2 of the 11 healthcare-associated cases clustered in space and time. One healthcare-associated case occurred in a patient receiving KHI-272 therapy, an oral, irreversible dual EGFR/HER2 inhibitor. The neonatal and maternal listeriosis cases were similar to those reported in the literature.

Conclusions. Nonclustered healthcare-associated cases of L. monocytogenes occurred at a large tertiary care hospital in Beijing, China. The source of these infections is unclear. Although rare, in the setting of immunosuppression, Listeria should be considered in the differential diagnosis of healthcare-associated infections, even in the absence of a point-source outbreak.

Increased Na+,K+-ATPase activity in the rat brain after meningitis induction by Streptococcus pneumoniae

Barichello T, Generoso JS, Cipriano AL, Casagrande R, Collodel A, Savi GD, Scherer EBS, Kolling J, Wyse ATS. Increase Na+,K+-ATPase activity in the rat brain after meningitis induction byStreptococcus pneumoniae.

Background: Pneumococcal meningitis is the most severe infection of the central nervous system with a mortality rate up to 20% and an adverse neurological result in up to 50% of survivors. A complicated series of interactions among the host immune response and oxidants seems to be responsible for meningitis associated brain dysfunctions. Na+,K+-ATPase is an essential enzyme responsible for generating and maintaining the membrane potential necessary for neural excitability, however, the Na+,K+-ATPase activity is altered in several illness;

Objective: The aim of this study is to evaluate the Na+,K+-ATPase activity in hippocampus and cortex of the rats submitted to pneumococcal meningitis.

Methods: Animals received 10 µl sterile saline as a placebo or an equivalent volume ofStreptococcus pneumoniaeto the concentration of 5 × 109cfu/ml and were killed at 24, 48, 72 and 96 h after meningitis induction. The brain structures, hippocampus and cortex, were immediately isolated on dry ice and stored at −80°C to analyse Na+,K+-ATPase activity.

Results: In the hippocampus, we verified the increase of Na+,K+-ATPase activity at 48, 72 and 96 h (p< 0.05) and in the cortex at 24 h (p< 0.05) after pneumococcal meningitis induction.

Conclusion: The Na+,K+-ATPase activity is under the control of a diversity of intracellular messengers that are able to modulate the function of the particular isozymes in a precise way. Furthermore, we verified that pneumococcal meningitis increased the Na+,K+-ATPase activity in hippocampus and cortex; this increase can be correlated with a compensatory mechanism in illness pathophysiology.

Clinical characteristics and prognosis of acute bacterial meningitis in elderly patients over 65: a hospital-based study

Background

To examine the clinical characteristics of bacterial meningitis in elderly patients.

Methods

261 patients with adult bacterial meningitis (ABM), collected during a study period of 11 years (2000-2010), were included for study. Among them, 87 patients aged ≥ 65 years and were classified as the elderly group. The clinical and laboratory characteristics and prognostic factors were analyzed, and a clinical comparison with those of non-elderly ABM patients was also made.

Results

The 87 elderly ABM patients were composed of 53 males and 34 females, aged 65-87 years old (median = 71 years). Diabetes mellitus (DM) was the most common underlying condition (34%), followed by end stage renal disease (7%), alcoholism (4%) and malignancies (4%). Fever was the most common clinical manifestation (86%), followed by altered consciousness (62%), leukocytosis (53%), hydrocephalus (38%), seizure (30%), bacteremia (21%) and shock (11%). Thirty-nine of these 87 elderly ABM patients had spontaneous infection, while the other 48 had post-neurosurgical infection. Forty-four patients contracted ABM in a community-acquired state, while the other 43, a nosocomial state. The therapeutic results of the 87 elderly ABM patients were that 34 patients expired and 53 patients survived. The comparative results of the clinical and laboratory characteristics between the elderly and non-elderly ABM patients showed that only peripheral blood leukocytosis was significant. Presence of shock and seizure were significant prognostic factors of elderly ABM patients.

Conclusions

Elderly ABM patients accounted for 34.8% of the overall ABM cases, and this relatively high incidence rate may signify the future burden of ABM in the elderly population in Taiwan. The relative frequency of implicated pathogens of elderly ABM is similar to that of non-elderly ABM. Compared with non-elderly patients, the elderly ABM patients have a significantly lower incidence of peripheral blood leukocytosis. The mortality rate of elderly ABM remains high, and the presence of shock and seizures are important prognostic factors.

Results of a cohort model analysis of the cost-effectiveness of routine immunization with 13-valent pneumococcal conjugate vaccine of those aged > or =65 years in the Netherlands

BACKGROUND

Community-acquired pneumonia and invasive pneumococcal disease are common among older people (ie, those aged > or =65 years). A new 13-valent pneumococcal conjugate vaccine (PCV-13) is under study in the Netherlands.

OBJECTIVE

The aim of this work was to model the cost-effectiveness of PCV-13 vaccination among those aged > or =65 years in the Netherlands, both in the total population and in those at increased risk for pneumonia, for various levels of efficacy (30%-90%) assumed.

METHODS

Our previously published cost-effectiveness model was updated to include age-specific epidemiologic data and health-care utilization and costs for a hypothetical cohort of adults aged > or =65 years in the Netherlands. This cohort was followed twice-once as unvaccinated and once as vaccinated-over a time period of 5 years, with differences between both analyses reported. Outcome measures included costs, life-years gained (LYGs), quality-adjusted life-years, and incremental cost-effectiveness ratios (ICERs). All analyses were performed from a societal perspective.

RESULTS

In the model, the ICER for vaccination remained below euro80,000/LYG, except when the vaccine was assumed to protect only against bacteremic pneumonia, with a relatively low effectiveness (40%) in combination with a high vaccine price (euro65), and indirect effects of serotype replacement would largely offset the direct effect of vaccination. For various assumptions, introduction of widespread PCV-13 vaccination (assuming a 60% efficacy against invasive and noninvasive disease because of vaccine serotypes, and a cost of euro50 per vaccinated person) was associated with the ICERs varying from cost-saving to euro50,676/LYG.

CONCLUSIONS

In this model analysis of a hypothetical cohort in the Netherlands, vaccination with PCV-13 might be considered cost-effective, both for the total population and for the high-risk population aged > or =65 years, from a societal perspective, over a 5-year time horizon. The main limitation of this study was uncertainty regarding how great a proportion of pneumonia could be attributed to pneumococcal disease.

Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis

The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in the United States and throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.

Community-acquired acute bacterial meningitis in the elderly in Turkey

This investigation aimed both to delineate the current status of community-acquired acute bacterial meningitis and to produce data on the interrelationships between clinical, laboratory and therapeutic parameters in the elderly. This retrospective cohort study was conducted in 28 Turkish institutions in 159 culture-positive patients over the age of 50 years. Streptococcus pneumoniae was the most common pathogen (69.2%), followed by Listeria monocytogenes (8.8%). For this reason, antilisterial antibiotics such as ampicillin or benzylpenicillin should be added to the therapeutic regimen. Pathogen-specific mortality did not vary between S. pneumoniae and L. monocytogenes. The overall mortality was 2.5% at the third day, 12.6% at the seventh day, 20.1% at the 14th day and 21.4% at the 21st day. The risk factors for fatality were increasing age, the presence of stupor, sepsis and inappropriate antibiotic administration. Cerebrospinal fluid (CSF) leukocyte counts and CSF/blood glucose ratios were lower in patients who died. Fever did not differ between survivors and fatal cases. The mean duration of antibiotic therapy in survivors was 16.3 +/- 6.4 days. One-fifth of the patients had complications, and in 5.7% of the patients sequelae persisted at follow-up.